If some vegetables are sold to him, he will leave the Dragonborn an inheritance of 100 when he faces his death (details and spoilers in the next paragraph). If stolen from, he will send Hired Thugs after the Dragonborn.

His death is inevitable, regardless of the Dragonborn's civil war affiliation, as his home is utterly destroyed during the catapult barrage on the city in the Battle for Whiterun. Completing the Battle for Whiterun quest or killing him manually could cause the Companions questline as well as Shalidors Writings (Ysgramor) to be incompletable, should they be attempted after his death. There is less post tax after the Battle for Whiterun for his inheritance pay.